Energy translating platforms incorporated into footwear for enhancing linear momentum

ABSTRACT

The present invention provides soles or platforms incorporated into footwear, preferably athletic footwear, designed to promote a more efficient running technique by an energy-translating sole comprising one or more foot-strike member, angular displacement member and balance-thrust member, as well as other conventional features. Systems and methods of the present invention promote more efficient running technique by facilitating foot-strike to occur at a point under and behind the runner&#39;s center of gravity. This is accomplished by the foot-strike member, angular displacement member and balance-thrust member working cooperatively to displace the runner&#39;s center of gravity and translate gravitational, inertial and ground reaction forces, as well as muscular tension forces, into linear momentum.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of co-pending U.S. provisionalpatent application No. 60/242,742, filed on Oct. 23, 2000. The priorityof the prior application is expressly claimed and its disclosure ishereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to athletic shoe technology. Moreparticularly, to systems and methods for various forms ofenergy-translating soles, or platforms, which are incorporated intofootwear and are designed to more effectively transfer gravitational,inertial and ground reaction forces into linear momentum therebypromoting a more efficient running technique.

[0004] 2. Description of the Related Art

[0005] Athletic shoe technology has undergone a revolution over the pastthirty years, particularly in regards to improvements in running shoes,both for the professional and casual user. In general, the majority ofadvancements in running shoe technology have largely centered aroundsupport, shock absorption and energy efficiency. For example, U.S. Pat.No. 5,909,948 describes an athletic shoe sole having a lateral stabilityelement to provide improved lateral support during heel-strike. U.S.Pat. Nos. 5,247,742 and 5,297,349 describe a cushioning sole forathletic shoes having a pronation control device incorporated into themidsole in order to increase the resistance to compression of themidsole from the lateral side to a maximum along the medial side, andU.S. Pat. No. 5,987,779 describes an athletic shoe having an inflatabletongue or bladder for a more secure fit.

[0006] A major focus in athletic shoe technology has centered on shockabsorption. A number of patents describe various systems for shockabsorption, such as air channels, miniature pumps, hydraulic systems,gas-filled bladders, elastomeric foam elements, pneumatic inflationdevices and spring elements. The following are illustrative of suchtechnologies: U.S. Pat. Nos. 5,598,645, 4,535,553, 5,325,964, 5,353,523,5,839,209, 5,983,529 and U.S. Pat. No. 4,763,426.

[0007] Embodiments of the present invention are distinct from theathletic shoe technologies pertaining to additional support or shockabsorption described above in that systems and methods of the presentinvention focus on improving running efficiency.

[0008] There have been several shoe systems related to increasing energyefficiency during running, such as U.S. Pat. No. 4,358,902, whichdescribes a thrust-producing shoe comprising a sole having fluid-filledcavities located in the heel and metatarsal portions with passagewaysinterconnecting the fluid-filled cavities. As the heel cavity iscompressed, fluid is forced through the passageways into the metatarsalcavities thereby providing shock absorption and forward thrust in theheel and metatarsal area.

[0009] U.S. Pat. No. 4,030,213 discloses a sporting shoe having anauxiliary sole member that is relatively thick under the toe portion andits outer surface is curved to form nearly a half circle at the forwardextremity of the toe section and the rearward extremity at the ball ofthe foot is relatively flat. An additional embodiment describes aplurality of recesses within the sole of the shoe for housing a numberof coil springs.

[0010] U.S. Pat. No. 4,506,460 describes a spring moderator for articlesof footwear, wherein a high modulus moderator is positioned beneath theheel or forefoot with a cushioning medium beneath the moderator. Thespring moderator operates to absorb, redistribute and store the energyof localized loads.

[0011] U.S. Pat. No. 4,936,030 provides an energy efficient running shoehaving an energy-transmission mechanism in the heel portion of the soleto transmit the mechanical energy of heel impact to the storage/thrustmechanism in the front sloe portion, where it is stored and releasedduring thrust. A number of embodiments are described havingsophisticated systems employing lever arms, coils springs, hydraulicassemblies and the like for capturing and transferring mechanicalenergy.

[0012] U.S. Pat. No. 4,949,476 discloses a running shoe having a hardfront sole for retaining gripping elements and, from the ball to theshank of the foot, an upwardly extending support cup on the outside ofthe shoe upper. The front sole extends into the shank portion of theshoe and covers a support wedge member. The wedge member extends fromthe ball of the foot to the shank and is progressively thicker towardsthe rear portion of the shoe. The wedge shaped member causes the foot tobe brought into an extended position for emphasizing contact with theground with the front outside ball region of the foot. Thisconfiguration serves to increase running efficiency by keeping the heelin an elevated position, which is the preferred attitude duringsprinting.

[0013] U.S. Pat. No. 5,586,398 provides an article of footwear for moreefficient running and walking wherein the contour of the outer sole atthe heel is formed at a dihedral angle to the medial/forefoot portionsin order to delay the instant of initial contact and thereby allow alonger length of foot flight and correspondingly longer stride length.An additional embodiment provides for friction management throughmaterials selection, surface coatings, or surface treatments designed toaffect friction across one or more interfaces between foot plantarsurface and shoe insole.

[0014] U.S. Pat. No. 5,647,145 describes a sculptured sole for anathletic shoe comprising a plurality of forward support pads, rearwardsupport lands, a layer of flexible resilient elastic materialinterconnecting various components, as well as a plurality of channels,grooves, slots and the like, which complement the natural flexingactions of the muscles of the heel, metatarsals and toes of the foot.

[0015] U.S. Pat. No. 5,680,714 discloses a trampoline effect athleticshoe having elastic return strips running across the sole of the shoeand supported above the bottom surface in a gap between the outersoleand insole.

[0016] U.S. Pat. No. 5,829,172 relates to shoe soles of running shoes,particularly for 100 m sprints and the like. The object of the inventionis to prevent the heel from touching the ground during running andthereby prevent a decrease in running efficiency. The sole comprises athickly formed forefoot section for receiving spikes. A Reinforcingmember provided in the ball region of the foot is integrated withreward-projecting medial and lateral ribs to form a wedge-shaped planeextending toward the heel. Medial and lateral ribs and reinforcingmember form a wedge-shaped inclined plane extending form the ball to thearch of the foot, which serves to maintain the weight distribution ofthe runner over the ball of the foot and hold the heel of the foot in anelevated position.

[0017] U.S. Pat. No. 5,743,028 describes a spring-air shock absorptionand energy return device for shoes in which a shoe heel insert isprovided having a heel-shaped outer spring mechanism which serves as aninternal spring housing wherein a plurality of compression springs areretained, and wherein the entire unit is filled with a pressurized gasand hermetically sealed.

[0018] U.S. Pat. No. 5,87,568 pertains to an athletic shoe wherein thesole has a rounded heel strike area and gently curved bottom thatgradually thins towards the toe section to permit the runner to rollsmoothly forward from the initial heel strike. Additional embodimentsfurther provide for a shock absorbing insert in the heel section.

[0019] U.S. Pat. No. 5,937,544 provides athletic footwear wherein thesole includes a foundation layer of semi-flexible material attached tothe upper and defining a plurality of stretch chambers, a stretch layerand a thrustor layer attached to the stretch layer such thatinteractions can occur between the foundation layer, stretch layer andthrustor layer in response to compressive forces applied thereto so asto convert and temporarily store energy applied to regions of the soleby wearer's foot into mechanical stretching of the portions of thestretch layer into stretch chambers. The stored applied energy isthereafter retrieved in the form of rebound of the stretched portions ofthe stretch layer and portions of the thrustor layer.

[0020] U.S. Pat. No. 6,006,449 and U.S. Pat. No. 6,009,636 relates tofootwear having various forms of spring assemblies incorporated into thesole, which serve to absorb shock and transfer energy.

[0021] While the prior art describes various systems for increasingrunning efficiency, these systems do not employ the unique features ofthe present invention. Rather than hydraulic or pneumatic systems;mechanical spring and/or lever assemblies; resilient elastic bands;alteration of the heel-strike region; or reinforcing structures tomaintain the heel in an elevated position, the present inventionprovides systems and methods that promote efficient running technique byproviding a sole comprising a specially designed foot-strike member andbalance-thrust member, which are integrated with a unique pivot andbalance structure that displaces the wearer's center of gravity whenrunning, thereby transferring gravitational, inertial and groundreaction forces, as well as muscular tension generation into linearmomentum. Systems and methods of the present invention are an advance inthe field of athletic shoe technology by providing a specialized soledesign for redirecting the forces encountered during running into linearmomentum, while reducing the shock and trauma to the body.

SUMMARY OF THE INVENTION

[0022] Systems and methods of the present invention provideenergy-translating soles, or platforms, for footwear, preferablyathletic footwear, designed to promote a more efficient runningtechnique. In one aspect, promoting a more efficient running techniqueis facilitated by an energy-translating sole comprising one or more ofthe following features: at least one foot-strike member, one or moreangular displacement members and at least one balance-thrust member, aswell as other conventional features.

[0023] In another aspect, systems and methods of the present inventionpromote more efficient running technique by facilitating foot-strike tooccur at a point under and behind the runner's center of gravity. Thisis accomplished by the foot-strike member, angular displacement memberand balance-thrust member working cooperatively to displace the runner'scenter of gravity and translate gravitational, inertial and groundreaction forces, as well as muscular tension forces, into linearmomentum.

[0024] In a further aspect, systems and methods of the present inventionprovide one or more foot-strike members, which may be situated in anylocation along the longitudinal axis (X axis) of the energy-translatingsole with a front zone extending into the forefoot area and a rear zoneoptionally extending into the heel section. Foot-strike member mayencompass the entire heel to forefoot sections, and/or any region therebetween. The medial and lateral margins of foot-strike member maygenerally follow the natural contours of the foot, and in embodimentswherein foot-strike member extends rearwardly to the heel, foot-strikemember generally follows the contour of the heel.

[0025] In yet another aspect, angular displacement member is generallylocated forward of foot-strike member, and is generally positioned inthe forefoot or metatarsal area of the foot. The front margins ofangular displacement member may extend well into the toe section of solewith the rear margin optionally extending along the longitudinal axiswell into the arch section of the sole. In a related aspect, variousembodiments employ specially configured angular displacement members tosuit particular running needs.

[0026] In another aspect, angular displacement member may have anynumber and/or sort of traction-related features, such as, but notlimited to, grooves, channels, ribs, points, raised projections of anysort, and the like.

[0027] In still yet another aspect, angular displacement member isgeometrically designed to provide a pivoting zone, preferably runningtransversely in the Z-axis between medial and lateral margins. Pivotzone may be located anywhere along the longitudinal axis (X-axis) withinangular displacement member depending upon the particular embodiment.Preferred embodiments of the present invention have pivoting zoneencompassing the metatarsal region of the foot rearward of the sesamoidbones of the first metatarsal bone.

[0028] In a further aspect, systems and methods of the present inventionprovide one or more balance-thrust members, which generally encompassthe toe section of the sole. Alternative embodiments may provide atleast one balance-thrust member further comprising a plurality oftraction facilitating members, such as spikes, teeth, ridges, groovesand the like. Medial and lateral margins of balance-thrust membergenerally follow the natural contours of the anatomical features of thefoot, but the overall configuration and orientation of balance-thrustmember varies with each particular embodiment.

[0029] In yet another aspect, the present invention provides a pluralityof embodiments specifically designed for different running needs, whichis partially dictated by the speed and distance involved. Eachparticular embodiment has a unique configuration and orientation offoot-strike member, angular displacement member and balance-thrustmembers to accommodate the unique biomechanical requirements of varioustypes of running.

[0030]

[0031] Other aspects of the present invention provide systems andmethods to effectively displace the runner's center of gravity andtranslate gravitational, inertial and ground reaction forces into linearmomentum. More specifically, systems and methods are provided whereinthe angle of displacement is directly related to the type and speed ofrunning, such that the faster the running speed, the higher the angle ofdisplacement and the more proximal to the toe region the pivot zone ofthe angular displacement member is oriented.

[0032] These and other objects, advantages, and features of thisinvention will become apparent upon review of the followingspecification and accompanying drawings.

BRIEF SUMMARY OF THE DRAWINGS

[0033]FIG. 1A shows a conventional shoe illustrating general features ofa running shoe typically found in the prior art.

[0034]FIG. 1B is a lateral perspective of the skeletal system of thehuman foot depicting the various anatomical features in relation toconventional footwear.

[0035]FIG. 2 shows a stylized plantar view of one embodiment of anathletic shoe sole of the present invention in spatial reference to thehuman foot.

[0036]FIG. 3 is a cross-sectional side view of an athletic shoeemploying systems of the present invention.

[0037]FIG. 4A is an alternative embodiment designed for distancerunning.

[0038]FIG. 4B is an additional embodiment designed for mid-distancerunning, such as a 1500 m race.

[0039]FIG. 4C shows yet another embodiment specifically designed forshort-distance sprints, such as a 100 m race.

[0040] FIGS. 5A-D illustrate the correlation of foot cycle, that is fromfoot-strike to angular displacement point, to angle ( ) of redirectionof energy into maximum linear momentum for and embodiment forshort-distance sprints, such as a 100 m race (5A), mid-to-long distancesprints, such as a 800 m race (5B), mid-distance running, such as a1,500 m race (5C) and long-distance running, such as jogging (5D).

DETAILED DESCRIPTION OF THE INVENTION

[0041] While the invention may be susceptible to embodiment in differentforms, the specific embodiments shown in the figures and describedherein are presented with the understanding that the description ofvarious embodiments is to be considered an exemplary of the principlesof the invention, and is not intended to limit the invention to that asillustrated and described herein.

[0042]FIG. 1A shows a generic form of footwear comprising an upper,indicated generally as 10, a midsole 12, an outsole 14, and an insole 16on the interior lower surface of the footwear. The shoe illustrated inFIG. 1A has a conventional shoelace 18 engaged in eyelets 20. Upper 10is partially split at the central, top portion of the footwear whereinlies some form of closure system 24, such as a conventional tongue.Collar 22 is provided to support the foot and/or ankle. Generallyspeaking, conventional shoes may be divided into heel (A), arch (B),ball or forefoot (C) and toe (D) regions. These elements of the footwearillustrated in FIG. 1A are generally conventional. Athletic shoes of thepresent invention comprise such conventional features, as well as othersin conjunction with a specially designed sole system. FIG. 1B is alateral perspective of the skeletal system of the human foot wherein theheel (A), arch (B), ball (C) and toe (D) regions of a conventional shoealign, in a general sense, with the anatomical structures depictedtherein.

[0043]FIG. 2 shows a stylized plantar view of one embodiment of anathletic shoe sole, namely an energy-translating sole 100 of the presentinvention, in spatial reference to the human foot. FIG. 3 depicts across-sectional side view of the same embodiment. In the broadest sense,systems and methods of the present invention provide anenergy-translating sole, or simply referred to herein as a sole,incorporated into shoes, preferably athletic shoes, comprising one ormore of the following features: at least one foot-strike member 102, oneor more angular displacement members 104 and at least one balance-thrustmember 106. As illustrated, there may be considerable overlap of thevarious members 102, 104, 106, but in alternative embodiments, members102, 104, 106, may not necessarily have appreciable overlap. In general,systems and methods of the present invention promote more efficientrunning technique by facilitating foot-strike to occur at a point underand behind the runner's center of gravity. Foot-strike member 102,angular displacement member 104 and balance-thrust member 106 workcooperatively to displace the runner's center of gravity and translategravitational, inertial and ground reaction forces, as well as musculartension forces, into linear momentum.

[0044] As will be described in greater detail below, systems and methodsof the present invention provide a plurality of embodiments specificallydesigned for different running needs, which is partially dictated by thespeed and distance involved. The particular embodiment depicted in FIGS.2 and 3 comprises footwear designed for running a mid-to-long distancesprint, such as a 400 m race. It is understood that the embodimentdepicted in FIGS. 2 and 3 are merely illustrative of the generalprinciples of the present invention and are not meant to be limiting inany respect.

[0045] Foot-strike member 102 is generally made of any conventionaldense, semi-deformable, wear resistant material, such as syntheticpolymers and plastics of any sort, having sufficient compliance andresiliency features to adequately absorb a relative portion of impactforces imparted to the shoe and body of the runner upon initial contactwith a supporting surface. Various embodiments of the present inventionmay employ materials that are more suitable for that particularapplication. For example, an embodiment for distance running may utilizea material for foot-strike member 102 having greater indices ofcompliancy and resiliency than an embodiment for sprinting. Foot-strikemember 102 comprises a front zone 112 extending towards toe section 126and a rear zone 114 extending towards heel section 120. In preferredembodiments, front zone of foot-strike member 112 is arcuately formed tofollow the natural anatomical features of the foot, but alternativeembodiments also include additional configurations (DT—IDEAS?) andfoot-strike member rear zone 114 generally follows the anatomicalmargins of the foot, such as the arch and heel. Foot-strike member 102may be situated in any location along the longitudinal axis (X axis) ofsole 100 with front zone 112 extending into forefoot section 124 rearzone 114 extending into heel section 120 and may encompass the entireheel 120 to forefoot 124 sections, and/or any region there between. Themedial 108 and lateral 110 margins of foot-strike member 102 generallyfollow the natural contours of the foot, and in embodiments whereinfoot-strike member 102 extends rearwardly to the heel, foot-strikemember 102 generally follows the contour of the heel.

[0046] Foot-strike member 102 may be of a singular uniform moldedcomposition or alternatively, be provided in a layered or compositeconfiguration. Plantar surface 116 of foot-strike member 102 may beintegral with and/or adjacent to any conventional outsole having anynumber and/or type of traction-related features, such as, but notlimited to, grooves, channels, ribs, points, raised projections of anysort, and the like. Furthermore, foot-strike member 102 may furthercomprise any conventional pneumatic and/or hydraulic cells, bladders,chambers and the like to further facilitate and control shockabsorption.

[0047] The configuration, dimensions and preferred constructionmaterials of foot-strike member 102, as well as angular displacementmember 104 and balance-thrust member 106, is largely dependent upon theparticular embodiment. The embodiment presented in FIGS. 2 and 3 showfoot-strike member 102 having a generalized elliptical form having athickness ranging from 0.5 to 10 cm, with front zone 112 taperingtowards, and transitioning with and/or into angular displacement member104 and rear zone 114 tapering and transitioning with and/or into one ormore support bases 158. Naturally, the tapered ends of foot-strikemember may fall outside the provided ranges. Support base 158 may be maybe integral with and/or adjacent to any conventional outsole having anynumber and/or type of traction-related features, such as, but notlimited to, grooves, channels, ribs, points, raised projections of anysort, and the like.

[0048] Angular displacement member 104 is located forward, towardsforefoot 124 and toe regions 126, of foot-strike member and is generallypositioned in the forefoot or metatarsal area 124 of the foot. Frontzone 128 of angular displacement member 104 is generally arcuatelydesigned and may extend well into toe section 126 of sole 100 and rearzone 130 of angular displacement member 104 may extend along thelongitudinal axis well into arch section 122 of sole 100.

[0049] Alternative embodiments envision angular displacement member 104being more compact, that is, encompassing less surface area, and morediscreetly positioned over the metatarsal and/or metatarsal-phalangesareas of the foot. Dorsal surface 134 of angular displacement member 104is integrated with or fixedly adhered to support base 158. Plantarsurface 132 of rear zone 130 of angular displacement member 104 isfixedly integrated with and/or adhered to dorsal surface 118 of fronttapering zone 112 of foot-strike member 102, such that a relativelysmooth transition between foot-strike 102 and angular displacement 104members is achieved and a strong, permanent bond or integral componentis provided. In preferred embodiments, plantar surface 132 of angulardisplacement member 104 may have any number and/or sort oftraction-related features, such as, but not limited to, grooves,channels, ribs, points, raised projections of any sort, and the like.Medial 136 and lateral 138 margins of angular displacement member 104generally follow the natural anatomical profile of the foot and,preferably, flow smoothly into respective medial 108 and lateral 110margins of foot-strike member 102.

[0050] Angular displacement member 104 is geometrically designed toprovide a pivoting zone 140, preferably running transversely in theZ-axis between medial 136 and lateral 138 margins. Preferred embodimentsof the present invention have pivoting zone 140 in the forefoot 124region, and more preferably encompassing the metatarsal region of thefoot rearward of the sesamoid bones of the first metatarsal bone,generally defined by circle 142. Pivot zone 140 may be located anywherealong the longitudinal axis (X-axis) within angular displacement member104 depending upon the particular embodiment. Pivot zone 140 may bevariously shaped, but in preferred embodiments, is arcuately formed tofollow the natural curvature and anatomical structures of the foot, suchas, but not limited to, the metatarsal-phalanges articulations, as wellas accommodate and exploit the natural lateral to medial rolling of thefoot during running. Systems and methods of the present invention aredesigned to promote more efficient running technique by facilitatingfoot-strike to occur at a point under and behind the runner's center ofgravity. Foot-strike member 102, angular displacement member 104 andbalance-thrust member 106 work cooperatively to displace the runner'scenter of gravity and translate gravitational, inertial and groundreaction forces, as well as muscular tension forces into linearmomentum.

[0051] Front zone of angular displacement member 128 is integral with,and/or fixedly adhered to, rear section 148 of balance-thrust member 106in an overlapping or abutting manner. Balance-thrust member 106 islocated forward (i.e., towards toe section 126) of angular displacementmember 104 and generally encompasses the front part of forefoot section124 and all of toe section 126 of sole 100. Depending upon theparticular embodiment, balance-thrust member 106 may be formed ofsemi-deformable material or essentially non-deformable material, but ingeneral, comprises a material having relatively less compliancy andresiliency than that of foot-strike member 102, such as conventionalsynthetic polymers and/or plastics, such that significant levels ofkinetic and mechanical energy are not overly dampened by deformation ofthe material. In select embodiments, such as depicted in FIGS. 2 and 3,as well as others, balance-thrust member 106 may be provided with aplurality of traction-facilitating elements projecting from plantarsurface 150, such as, but not limited to, spikes, teeth, cleats, ridgesand the like. Such traction-facilitating elements may be fixedlyconnected to, and/or releasably integrated with, and/or integrallyformed from balance-thrust member 106 by any conventional methods.Choice of construction materials for balance-thrust member 106 shouldhave sufficient hardness, as determined by conventional methods, toretain traction-facilitating elements and effectively transmit forcesfrom sole 100 to supporting surface and vice versa.

[0052] Front zone 146 of balance-thrust member 106 extends up to, and inselect embodiments, extends beyond, the phalanges distal margin of thefirst metatarsal bone. Front zone 146 of balance-thrust member 106 endsin a termination point 160, which may be in the form of tractionfacilitating members, such as spikes, teeth, ridges, grooves and thelike, depending upon the particular embodiment. Termination point 160may be variously located long the longitudinal axis (X-axis) of sole100. For example, FIG. 2 depicts a shoe designed for mid-to-longdistance sprinting and has termination point 160 at adownward-projecting angle and extending somewhat beyond the forwardperimeter of support base 158 and upper 10, but other embodiments, suchas a distance shoe and/or jogging shoe, may have termination pointextend even further beyond the forward perimeter of support base 158 andupper 10 and not have as pronounced a downward projecting angle. Medial154 and lateral 156 margins of balance-thrust member 106 generallyfollow the natural contours of the anatomical features of the foot. Aswith other aspects of the present invention, plantar surface 150 area ofbalance-thrust member varies with each particular embodiment. Forpurposes of example, select embodiments, such as in FIG. 2, lateralmargin 156 may define a more focused balance-thrust member, that is,delineate plantar surface 150 area of balance-thrust member 106 toencompass the first through fourth metatarsal-phalanges areas of thefoot, such that horizontal propulsive forces at toe-off are effectivelyfocused on the most relevant parts of the foot.

[0053] FIGS. 4A-C depict various embodiments of the present invention.As previously mentioned, systems and methods of the present inventionare variously configured to accommodate different types of running, suchas, but not limited to, long-distance running or jogging (FIG. 4A),intermediate distances, such as 1,500 m racing (FIG. 4B), mid-to-longdistance sprints, such as 400 m racing (described in detail above and inFIGS. 2 and 3), and short-distance sprints, such as 100 m racing (FIG.4C).

[0054] Kinesiological analysis of running has demonstrated differenttypes and speeds of running involve different biomechanics. During arunning cycle involving a heel-strike, such as jogging, various portionsof the foot undergo a number of movements and are exposed to variousforces. When foot-strike, that is heel-strike, is initiated, the foot isin supination and as contact progresses pronation permits partialabsorption of impact forces. As the foot transitions from mid-support totakeoff, resupination, or transfer to the lateral ball portion of thefoot occurs as the foot becomes a rigid lever. The continuous motiontransfers from lateral to the medial ball of the foot as the footaccelerates through toe-off. In contrast, during sprinting, the groundstrike occurs in the forefoot or metatarsal area of the foot and thepoint of impact tends to be under or slightly behind their center ofgravity. As a result, this form of running has less of the decelerationphase associated with heel-strike running and propels the body massforward more efficiently.

[0055] Systems and methods of the present invention provide a range ofembodiments to accommodate these biomechanical requirements. In general,the angle of displacement is directly related to the type and speed ofrunning. In short, the faster the running speed, the higher the angle ofdisplacement, as depicted by pivot zone profile 170, and the moreproximal to the toe region 126 the pivot zone 140 is oriented. Thesesalient points are most clearly illustrated by contrasting respectivefoot-strike 102′, 102′″, angular displacement 104′, 104′″ andbalance-thrust members 106′, 106′″ in a distance-running embodiment(“running shoe”- FIG. 4A) versus a short-sprint embodiment (“sprintingshoe”- FIG. 4C). As clearly illustrated, the distance-running shoepresented in FIG. 4A has a more extensive foot-strike member 102′, withrear zone 114′ of foot-strike member 102′ extending to completelyencompass heel section 120, and is substantially thicker to moreeffectively absorb impact forces, whereas the embodiment designed forsprinting illustrated in FIG. 4C, has a limited foot-strike member 102′″with rear zone 114′″ of foot-strike member 102′″ extending from theforward section of the arch region 122 into the forefoot region 124.Foot-strike member 102′″ of the embodiment designed for sprinting isoriented to accommodate a running style wherein initial contact with thesupporting surface is predominantly in the forefoot area of the foot.Angular displacement member 104′ of the distance shoe has a lower pivotarea profile 107′ as compared to the angular displacement member 104′″of the sprinting shoe's pivot area profile 170′″. Additionally, angulardisplacement member apex 172 for the running shoe is located relativelyrearward along the longitudinal axis (X-axis) in relation to angulardisplacement member apex 176 for the sprinting shoe. Furthermore,balance-thrust member 106′ of running shoe encompasses a greater surfacearea of toe section 126, and in some embodiments, front zone 160′ mayextend beyond toe section of upper, whereas, balance-thrust member 106′″of sprinting shoe encompasses comparatively less surface area.

[0056] During a running cycle, as the initial foot-strike makes contactwith the supporting surface, there is a certain amount of supination andthe foot is slightly ahead of the center of mass, which serves tominimize deceleration forces and to preserve linear forward momentum.The talocalcaneal, or subtalar, joint plays a major role in convertingthe rotary forces of the lower extremity into forward motion. Inoperation, systems and methods of the present invention build upon thesenatural movements by assisting foot-strike to occur at a point under andbehind the center of gravity.

[0057] Following contact with the surface, the support phase isinitiated, wherein the runner's body mass is fully supported. As theknee flexes to absorb impact forces and support the runner, the ankleplantar flexes and the subtalar joint pronates, causing heel pronation.Heel pronation permits absorption of compressive shock forces, torqueconversion, adjustment to uneven ground contours and maintenance ofbalance. Eccentric tension in the posterior tibialis, soleus andgastrocnemius muscles cause deceleration of subtalar joint pronation andlower extremity internal rotation. Pronation reaches its maximum duringthis time and resupination is initiated to permit the foot to passthrough its neutral position at the midpoint of the support phase. Whenthe runner's center of mass is at its lowest position, a maximumvertical force is actively generated and transmitted to the supportingsurface by the muscles and is often referred to as the active verticalforce peak. This active vertical force peak typically reaches 2 to 8times body weight, depending on the speed of the runner. It is duringthe support phase that angular displacement member 104, and moreparticularly, pivot region 140, engage supporting surface, initiatingdisplacement of the runner's center of gravity. Systems and methods ofthe present invention serve to minimize the support phase, therebyconserving biomechanical energy by limiting energy lost to thesupporting surface. Furthermore, embodiments of the present inventionreduce shock and trauma to the runner by redirecting gravitational andinertial forces into linear momentum.

[0058] The support phase continues until the heel begins to rise intotakeoff during the recovery phase. Generally speaking, the recoveryphase is the stage of running in which muscular tension exerts verticaland horizontal forces to the support surface to propel the runnerforward. During this time the foot converts from a shock-absorbingstructure to a rigid lever for forward propulsion, which is largely dueto changes in position of the subtalar and midtarsal joints, and inparticular, supination of the subtalar joint . As the knee jointextends, the lower extremity rotates externally, the calcaneus inverts,the midtarsal joint locks and the foot becomes a rigid lever. Thepropulsive force is a thrust backward and downward resulting from acombination of hip extension, knee extension and ankle plantar flexion.During the recovery phase, the rotational movement of the runner's footundergoes a second rotational movement as the runner rolls throughangular displacement and balance-thrust members 104, 106, respectively,incurring greater angular acceleration and thereby further displacingthe runner's center of gravity forward and translating gravitational,inertial, ground reaction, and muscular tension forces into linearmomentum.

[0059] These principles are more clearly presented in FIGS. 5A-D, whichillustrate the correlation of a foot cycle, herein defined as being frominitial foot-strike to angular displacement point, to angle ofredirection of energy ( ) into maximum linear momentum. In general, theangle of displacement required for maximal redirection of energy isdirectly related to the type and speed of running and the faster therunning speed, the greater the angle of displacement becomes. Forexample, embodiments designed for short-distance sprints, such as a 100m race (FIG. 5A) have a comparatively low foot cycle radius (r), whereasembodiments designed for long-distance running (FIG. 5D) have arelatively large foot cycle radius (r′″). Furthermore, foot cycle radius(r) is inversely proportional to the angle of redirection of energy ( ).In other words, embodiments designed for short-distance sprinting (FIG.5A) require a larger angular displacement profile 170.

[0060] While in the foregoing specification this invention has beendescribed in relation to certain preferred embodiments thereof, and manydetails have been set forth for purpose of illustration, it will beapparent to those skilled in the art that the invention is susceptibleto various changes and modification as well as additional embodimentsand that certain of the details described herein may be variedconsiderably without departing from the basic spirit and scope of theinvention.

What is claimed is:
 1. A shoe having an upper and a foot supportingmember, the foot supporting member comprising: a substantially rigidmember having a dorsal surface and a plantar surface; the plantarsurface having a convex portion and an adjacent concave portion, theconcave portion extending forward past the tips of the digits andterminating distally at a downwardly projecting balance-thrust member.2. A shoe according to claim 1 further comprising the plantar surfaceconvex includes a curved angular displacement surface below the sesamoidapparatus of the first metatarsal phalangeal joint and defining a firstaxis of rotation of the foot.
 3. A shoe according to claim 2 furthercomprising the balance-thrust member defining a second axis of rotationof the foot forward of the wearer's foot.
 4. A shoe according to claim 2further wherein curved angular displacement surface and balance thrustmember are positioned so that when both are in contact with ground, thesesamoid apparatus is elevated with respect to the digits.
 5. A shoeaccording to claim 1 further comprising a foot strike member adjacentthe convex surface.
 6. A shoe according to claim 1 further comprisingthe dorsal surface including a concave portion having a curvatureselected to support the digits of the wearer's foot in a dorsiflexedposition relative to the metatarsals.
 7. A shoe having an upper and afoot supporting member, the foot supporting member comprising: asubstantially rigid member having a dorsal surface and a plantarsurface; the plantar surface having a convex portion and an adjacentconcave portion, the concave portion extending forward past the tips ofthe digits and terminating distally at a downwardly projectingbalance-thrust member; the plantar surface convex portion including acurved angular displacement surface below the sesamoid apparatus of thefirst metatarsal phalangeal joint and defining a first axis of rotationof the foot; and, the balance-thrust member defining a second axis ofrotation of the foot forward of the wearer's foot.